Mt mk1 boot lock has given up working. But now I can't get into the boot.
Does anyone know how to get the boot open? Preferably without too much damage

Ah yes. The speaker hole. I was wondering how get the back seat out without opening the boot.
I'll have a look at getting the backrest out, its still going to be a long reach to get at the boot lock though.

Don't forget that Mk1s have a firewall behind the rear seat, unlike most Mk2s. So I'm not sure that removing the rear seat back is going to be of much help.
 
How about getting hold of as many ratchet extension bars as you can with the correct sized socket on the end and feeding it through the speaker hole to undo the two latch bolts?! Sorry Peter, not sure what else to suggest - breaking into cars isn't my forte!
 

Yeah Simon, I was thinking that about the firewall before. I got into a mk2 boot by threading myself through the braces, but the mk1's are a bit more blocked up.
I need to find a gibbon with really long arms that can get to the nuts for me
Or go and steal a heap of my father in laws extensions. That might just work. Either way its gonna be a dog of a job

Its not too hard to do.
Get a bit of stiff wire (coathanger) straighten it out  then put  a 90 degree bend about 75mm from  the end and curl the other end around to give something to grip.
Then carefully prise off the O in ford lettering which will give a hole with witch to stick the wire.
There is a tab in there that will push to the right, unlocking the lid. It sits just to the right of the lock barrel ( the cam  thingy on the end of the lock barrel pushes against the tab when you turn the key.) You might have to lengthen the wire or shorten it but its quite doable. Good luck.

What exactly is the lock doing/not doing??
 
Most wreckers will have a box of escort keys.
Try alternative keys (or your own escort key, if not try keys from other older vehicles) and jiggle key around firmly whilst trying to open lock.
The jiggling action usually catches some parts of the worn mechanism. Usually that works.
 
If desperate and if the lock is of no value find a nice long sharp flat blade screw driver and force it into the lock and open. Do not force too much otherwise will destroy the paint on the boot lid.
 
There is no such thing as an escort lock that cannot be opened. It is worn out 45 year old technology.
 
 

This has happened to me a few times with my MK1 boot. Simon was right, lift the back seat off and using as many ratchet extensions as needed, and a 7/16 or 1/2 socket,  remove the bolts from the latch and the boot will pop open.
From there it isn't too hard to remove the barrel and give it a clean up or what ever is needed.
Hope this helps?

Visit the local skate park, surely one of the boys there will get it open for you.

Dont understand what you guys are stressing about, just get a steel ruler and place it underneath the barrel to protedt the paintwork, then use a screwdriver to gently prize out the barrel. it will just fall out, then put your finger into the hole and unlatch it. Bloody simple, done it many times on my car with its brand new paintjob and never left a mark.